Videos of Cyrus, holding up a cardboard cutout of Gomez while singing the song "FU," have made their way online, and it looks like the prelude to a celebrity feud. In the clip, Cyrus, 21, wears a canary dress as she sashays around the stage with cardboard Selena under her arm. The cutout features a smiling Gomez, 21, with a black bikini top crudely drawn on her cardboard body.

Cyrus passionately sings the lyrics of her angry song, which seemed more aimed at a spurned ex-lover than a former pal: "Why, why you're doing what you do. You, you might as well just tell the honest truth," she croons.

"See, I'm not really down with this. This ain't no texting s---. Know I got no biz, but it is what it is," she continues, before flinging the cardboard into the crowd. She then turns to a giant furry creature and sings to it.

Though it remains unclear what the Cyrus-Gomez beef might be, the twerking pop star has a good rapport with Gomez's ex, Justin Bieber.

Both Cyrus and Gomez performed together back in 2008 at the Teen Choice Awards when Cyrus starred as Hannah Montana on the eponymous smash series. Gomez, during that time, starred on Wizards of Waverly Place, in addition to multiple Disney Channel original movies. In 2007, she guest-starred on Cyrus' show, and ironically, played Hannah's rival on a three-episode arc.